It is also possible that I am confusing this for something else. It is possible I'm getting some eastern and western cultural concepts mixed in my head, or maybe something else. As I said, this isn't an issue that comes up all that often.

Never mind. What you know is fact of history, but these social standard already ended at Pre-war Showa era. At Edo, Meiji, Taisho era, 勘当(kandou）really was expellment from family, and surrounding social community. But it requires Bureaucratic paperwork, very serious movement for cut off family relations.

Now, in modern Japan, that term means gets mild.

Usually, Kandou means expression of "I don't want to see your face, go anywhere and live yourself, lad" from parents, or Leader of Family, at confrontation of family affair. Many time, it only means harsh insult term for child. That makes heart cry, but no more.

In other way, person who gets pronounce of Kandou, must leave from house, but many case, it just cause for change living place from family home to another, like relative's house, or domitory of school or company, or simply, rent a room. But not so serious social matter as old society custom.

Many case, especially minor age, children gets funding which had time limit from parents until graduate school and get job for living oneself. Then, sail away for new world by own.

But this not means total separation. Other family member except Leading Family Person (father, sometime mother, or grandparent) who pronounce Kandou keep in touch, in many case. You can see these situation in many story.